Long ago, Ted Cruz earned the hatred of every elected Democrat in Washington. Now, he’s on his way to doing the same with nearly every Republican. Soon, it will be almost a clean sweep.

He had barely begun his 21-hour filibuster — or, to be strictly precise, 21-hour-long speech — when he compared his doubters to appeasers of Adolf Hitler, and he ended it roughly a day later with a prickly exchange with Senate Majority Leader Harry Reid.

The Cruz eye-rollers had plenty of occasions to roll their eyes — perhaps no senator has caused so many colleagues to mutter under their breaths in his first eight months in the world’s greatest deliberative body — but the conservative grass roots cheered.

We should stipulate upfront that he is not going to defund Obamacare. As a legislative strategy, the defund effort is far-fetched to the point of absurdity. The theory is that on the cusp of or after a government shutdown, pressure becomes so intense on Democrats that Reid buckles and passes a measure defunding Obamacare, and Barack Obama signs it.

Let’s put aside for the moment that Democrats believe — probably rightly — that Republicans will be blamed for any shutdown. Why would a little downside political risk in the current confrontation move them? We’re talking about a party that spent decades trying to pass something like Obamacare and a president who was content to lose his House majority over it.

The Cruz all-nighter wasn’t a legislative tactic so much as it was what 19th-century anarchists called “the propaganda of the deed.” It made a point. It dramatically reaffirmed Republican resolve to repealing Obamacare. It drove more debate about the health-care law. It perhaps opened up space for more realistic immediate Republican goals, such as a delay in the individual mandate, in the impending fiscal fights.

It also saved Cruz’s reputation among the tea-party conservatives. The House passed its defunding measure in a passive-aggressive mood, as if to say, “All right, big guy, you wanted this -- now let’s see what you can do with it.” The reaction in the House when Cruz said the measure didn’t have the votes in the Senate was anger combined with schadenfreude at his presumed comeuppance. Rarely have so many harsh background quotes been given to so many reporters with such glee.

In the longer run, the outcome in the short term is irrelevant to Cruz’s stature as a conservative leader. No one asked whether Ronald Reagan had successfully blocked the ratification of the Panama Canal Treaty in 1977 when he ran for president in 1980. For that matter, no one asked whether Sen. Barack Obama had successfully defunded the Iraq War in 2007 when he ran for president in 2008.

Obama’s example is instructive: When before have we heard of a new senator capturing the imagination of his party’s base, establishing an unimpeachable standard of purity on a hot-button issue absolutely essential to it and beginning to run for president shortly after arriving on the national scene?

Who knows whether Cruz ultimately tries the same thing. But the scoffers are probably the same kind of people who chuckled at backbencher Newt Gingrich giving speeches to an empty House chamber on C-SPAN so many decades ago. Gingrich was playing an outside game, and so is Cruz. The disdain for him among insiders will be inversely related to the admiration for him among the much more important outsiders.

They will sustain him in a crusade against Obamacare that, alas, will extend long beyond this fall’s fiscal fights.

(Daily Corinthian columnist and editor of the National Review, Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.)